South Carolina joined the SEC in 1992 and in that same year Mississippi State played them for the first time. Prior to that, USC was an independent for 20 years after leaving the ACC in 1972. They were also members of the Southern Conference prior to that.
1992: South Carolina 21, #15 MSU 6
Sparky Woods was the Gamecocks coach for this first match-up. The game was played in Columbia and obviously one of the more disappointing losses of the season as State was 4-1 and highly ranked.